Apparatus for testing and measuring the strength or resistance of materials.



No. 720,575. PATENTEDI'EB. 17, 1903.

0. FREMONT. APPARATUS FOR TESTING AND MEASURING THE STRENGTH OR NO MODELRESISTANCE OF MATERIALS 1 APPLIGATION FILED JULY w r a K Mg T 1 O g'm 5550 05 '10 55 50 g5 g 15 10 d59- F 6 A NITED; STATES PATENT OFFICE.

CHARLES FREMONT, ()F PARIS, FRANCE.

APPARATUS FOR TliSTlNGgAND MEASURING THE STRENGTH 0R RESISTANCE OFMATERIALS.

SPECIFICATION forming part of Letters Patent No. 720,575, dated February17, 1903.

' Application filed Jul 16,1902. serial No. 115,780. (No model.)

T0 at whom it may concern.-

Be it known that I, CHARLES FREMONT, a citizen of the Republic ofFrance, residing at Paris, France, have invented certain new and usefulImprovements in Apparatus for Testing and Measuring the Strength orResistance of Materials, of which the following is a specification.

This invention relates to an apparatus which will permit of testingandmeasuring the strength or resistance of finished articles and ofmaterials wherein stamps are employed to produce blows or shocks uponthe materials or articles to be tested. These materials are generally ofmetal or alloys of metals which can be tested in the form of bars or invarious forms and sections.

Whatever may be the constitution or shape of the materials to be testedthis improved measuring apparatus renders it possible to ascertain theirdegree of resistance.

The apparatus comprises a stamp or drophammer provided with a punch orhead which falls and effects the necessary blow to determine theresistance-shock of thematerial.

The stamp or drop-hammer l carries a punch- 2, which is destined to comein contact with and bend or' break the article or bar to be tested, thelatter being placed upon the support 15 previous to the fall of thehammer. After the breakage of the bar the hammer still possesses a forcewhich is taken up by springs 4:, the latter being compressed'proportionately to the amount of work expended after the breakage ofthe barg'but as the springs expand immediately it is necessary to havean index which follows exactly the compression of the springs 4 andrecords their momentary maximum compression. As the force of impact ofthe hammer is very great, the pointer employed for marking the extremelimit of travel or compression of the springs is operated by such alarge force that it is liable to overflow and indicate a compressiongreater than the real compression. In order to avoid this error, theyare strongly compressed; but then the friction of a pointer under theseconditions requires, in order to be overcome, a large expenditure ofwork, which is taken from the power of the hammer. It is this which isthe first cause of error. after several operations the frictiondiminishes rapidly, and the pointer is then projected farther thanbefore for the same blow of the hammer under the same conditions, andthus a second error occurs. As the com pression of the springs 4 cannotbe very great and as it should be divided into many parts to permit ofreading to a close approximation the expenditure of work, it isnecessary to amplifythe movement of the spring, and it follows that anindex conforming to these conditions has necessarily a great volume anda great weight and absorbs so much more power. The improved apparatusaccording to this invention remedies these defects.

This apparatus for measuring and registering the resistance of materialsto shocks is constituted mainly by the following three parts:

a. A metallic friction rod or tube 5 of Very lightweight, made ofhardened steel, for example.

b. A brake composed, for example, of two blocks of wood 6, between whichslides with slight friction the tube 5 upon a bed or packing of felt,cloth, flexible or soft leather, or other analogous material fordistributing the friction over the whole surface in contact with thetube. 'A flat spring 7, regulated by a screw 8, produces a uniform andsufficient pressure upon the block 6, so that the sliding of the tube 5prevents the hammer 1 by slight friction from exceeding the limit ofmovement of the springs 4.

c. A lever 9, independent of the tube 5, which multiplies the movementof the springs 4 by three or four times, for example, and

Furthermore, this friction varies, and

permits of an easy reading of the work expended upon a scale 12. Thislever is preferably of the bell-crank form, and has a long arm 9arranged, preferably, in the vertical direction, while its short arm 10is relatively heavy and horizontal, so as to displace the center ofgravity of the lever and to insure that it always shall be to the rightof the axis of oscillation 11, so as not to interfere with the movementof the tube 5, which it never touches, even when the latter reaches thelimit of its travel, which corresponds to the extreme compression of thesprings 4.

When the hammer 1 falls, it compresses the springs 4 in proportion tothe amount of @118 m'ra left after the breakage of the article to betested placed upon the support 15. The tube 5 moves downward positivelyor exactly in accordance with the compression of the springs t withoutexceeding it, owing to the friction brake-blocks 6, and affords anaccurate index to the extent of compression of the springs 4. In orderto measure this compres sion, it is suificient to draw the arm 9 of thebell-crank lever toward the left until the end of its lower arm lO-comesin contact with the tube 5, and to read on the graduated dial 12 thefigure indicated by the pointer 9 in order to ascertain the amount of msviva which remained in the hammer after the breakage of the bar. As theamount of the initial force is known, being equal to the product of theheight of fall of the hammer multiplied by its weight, the work expendedin effecting the breakage of the bar can be immediately ascertained bydeducting the amount indicated by the pointer from the total powerapplied. As the extent of fall of the hammer is preferably constant inorder to avoid the necessity of working out the result, the dial 12 maybe graduated, so that the pointer 9 will give at once the result sought.Thus a single reading gives the required figure which is indicated bythe pointer 9 of the lever. After reading this result the apparatus isbrought back to zero by pressing upon the long arm of the lever in orderto cause the arm 10 to press the tube 5 upward against the under side ofthe plate 30, which is sustained by the springs 4L and 40, whereupon theapparatus is ready for a fresh operation. The tube 5 being very lightoffers only a very small resistance and requires only a little frictionto hold it, while it is not driven forward by momentum, but

only to the exact extent corresponding to the power exerted, andconsequently it acts positively and cannot produce the errors referredto above. Further, the bell crank lever which multiplies the extent ofmovement of the springs 4 being independent of the tube 5 is not thrownforward during the shock, but effects the multiplication exactly and canbe used to efiect the return of the tube 5 to its initial position.

What I claim as my invention, and desire to secure by Letters Patent,is-- 1. Apparatus for testing metal and other articles comprising adrop-hammer a rigid work-support a spring-supported plate intermediatethe work-support and the hammer in combination with a scale-pointer anda positively-acting pointer-operating mechanism intermediate thespring-supported plate and the pointer substantially as described.

2. Apparatus for testing metal and other articles comprising adrop-hammer a rigid work-support a spring-supported plate intermediatethe Work-support and the hammer in combination with a frictionally-heldrod the upper end of which is normally in contact with the under surfaceof the plate and an independently-mounted bell-crank lever one arm ofwhich is adapted to be brought in contact with the lower end of the rodafter the hammer has dropped while its other arm acts as a pointer on agraduated scale substantially as described.

3. In apparatus of the kind described a frictionally supportedtransmission device intermediate the spring-supported plate and thepointer comprising a light rod a brakeblock in contact with said rod andmeans for pressing the block upon the rod substantially as described.

4. Apparatus for testing metal and other articles comprising adrop-hammer a worksupport with an intermediate spring supported plate 30a rod 5 frictional brake-block 0 and a bell-crank pointer-lever 9 10substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

CHARLES FREMONT.

Witnesses:

ALBERT MAULvAULtr, EDWARD P. MAOLEAN.

